Flame cutting tip

ABSTRACT

A flame cutting tip having its externally tapered core held resiliently in contact with an internally tapered sleeve to provide an improved heat exchange and sealing relationship in a radial direction between the parts which is readily released and assembled manually without tools for quick interchangeability of tips and parts along with the tactual feeling of terminal tightness during the last appreciable distance of relative movement.

United States Patent 1,977,782 10/1934 Thomas 239/424.5X of terminal tightness during the last appreciable distance of 2,117,751 5/1938 Walker 239/422X relativemovement.

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1 L I 290 f 7o 57 I 7l 5 {4 37 Inventor Francis J. Eichelman La Grange Park, 111. Appl. No. 875,744 Filed Nov. 12, 1969 Patented Sept. 14, 1971 Assignee The Golconda Corporation Chicago, 111. Continuation-impart of application Ser. No. 775,397, Nov. 13, 1968, now abandoned.

FLAME CUTTING TIP 19 Claims, 16 Drawing Figs.

US. Cl 239/4193,

239/422, 239/424, 239/596, 239/600 Int. Cl F23d ll/l6 Field of Search 239/290, 418, 422, 423, 424, 424.5, 428, 419.3, 596, 600

References Cited UNITED STATES PATENTS Primary ExaminerM. Henson Wood, Jr. Assistant Examiner-Edwin D. Grant Attorney-Harbaugh and Thomas ABSTRACT: A flame cutting tip having its externally tapered core held resiliently in contact with an internally tapered sleeve to provide an improved heat exchange and sealing relationship in a radial direction between the parts which is readily released and assembled manually without tools for quick interchangeability of tips and parts along with the tactual feeling PATENTEDSEPMIBYI 3.604.632

SHEET 2 OF 3 I NVENTOR.

FRANCIS a. EICHELMAN ATTY'S I NVENTOR.

m/ x .W.

FRANCIS J. EICHELMAN BY M SHEET 3 0F 3 PATENTEU SEP 1 4 l97l 5 m ow MTQE 5 fin 9mm n w and ATT'YS FLAME CUTTING TIP CROSS REFERENCES This application is a continuation-in-part of application Ser. No. 775,397 filed Nov. 13, 1968, now abandoned.

BACKGROUND OF THE INVENTION In cutting or piercing metal with oxygen the metal must be preheated to the ignition temperature before the cutting stream of oxygen is applied in a well-known manner. This preheat can be done with any saturated hydrocarbon gas such as propane or natural gas as a fuel gas mixed with oxygen to provide an optimum combustible mixture which is directed through a plurality of preheat ports that are peripherally spaced closely around a central or cutting port through which the cutting oxygen is discharged whereby the flames preheat the metal where the cutting oxygen is going to strike. It is highly desirable that the gas mixture flowing through the preheat ports has constant predetermined set ratios, both for preheat starting and during cutting operations, and also provides uniform flames as to length and cross-sectional configuration for cutting movements in any direction.

Although the cutting tip can have preheat passages that are drilled and swaged in copper bodies for preheat flame uniformity, it will be appreciated that production costs are important considerations for interchangeability of parts and for an expendable product experiencing a comparatively short working life. Moreover, a reflected high-cutting heat is absorbed at the end of the tip and can be conducted the length and thickness of the tip. Generally, in an endeavor to retard conduction of heat to the base of the tip and torch head, a brass core is employed having approximately one third the heat conductivity of copper and the preheat passages comprise longitudinal channels externally cut in a tapered surface on the brass core around the cutting port. A correspondingly internally tapered copper sleeve is then wrench-tightened solidly against the taper surface to convert the channels into passages leading to the preheat ports and in order to convey the appropriate gases from the torch head to the passages in the tip seal all gas-tramsmitting joints at the other end of the core and sleeve. These other joints are separately machined and are either cut on a taper or associated with a retainer that is cut on a taper and the mating frustoconical portions must seal that bound mating gas-transmitting concentric grooves in the tapered cavity and torch head.

It will be appreciated that even under close manufacturing tolerances required for these assemblies, discrepancies do occur in the relative lengths designed for the core and sleeve and this causes misfits or seal breaks at the three or four mating tapered joints involved and therefore each pair of cooperating tip parts has to be selected and virtually hand fit for use together. It is a rarity that all contacting conical surfaces will interchangeably engage in sealing relationship under conventional manufacturing tolerances without heavy wrench-tightening the assemblies to establish compressionsealing between metal parts at all proper places. This tightening and the necessary manufacturing tolerances for such to be assured can cause flame distortion or destruction of the tip elements and is often evidenced by the tip of the core being damaged by being twisted helically if the core has a predominantly plus and the sleeve a negative tolerance factor.

Discrepancy of uniform contact at the channels permits irregularities to occur in the preheat flame patterns and if the rate of flow of mixed gases in indiscriminate places falls below their flame propagation rate and dangerous flashbacks can occur, or some flames are longer than others. This latter not only displaces the relative working points of the flame with respect to the workpiece but lowers the overall effectiveness of the tip and requires additional gas volumes.

These discrepancies can be readily detected by visual observation of the flames and some corrections can e made, but crossleaks between unmixed gas passages changes the proportions of the mixtures at the flames with well-known objectionable results including tip heatups, uneven thermal expansion of the parts and very often damage to the parts from overtightening to stop leaks.

SUMMARY OF THE INVENTION in the present invention, in seeking to provide seals that permit relative longitudinal moyement between the tip parts to eliminate the need for close tolerances and to provide universal interchangeability of the parts including cores having different port sizes, resilient means is utilized to urge a floating core forwardly in sealing relationship with the sleeve of the tip. This is accomplished in one or both of two ways, by the pressure of the gas being discharged through the tip being effective over the inner end of the core, either with or without a compression spring being present. in either event, the inner end of the core is open to this gas pressure and is provided with a radial seal between the core and sleeve so that the core is slidably received in the sleeve. If a spring is also to be used, space to receive it between the inner end of the core and the torch head is provided to accommodate the spring. Otherwise this space can be limited within wide tolerance and the overall length of the tip or the head reduced with a substantial saving in material.

in both instances the inner end of the core can be square and with a compression spring present the spring action also simulates a habitual feel of a tightening that is associated with tapered surfaces. Also in both, the uniformity of flames in each tip is invariably correct and constant notwithstanding wide tolerance variations. Moreover, it is not necessary to wedge the core and sleeve by a wrench-driven threaded relation to overcome creep or relative metal flow between the parts occurring with repeated warrnups and cooloffs causing differential thermal expansion.

Furthermore, molded ceramic cores can be used whose tolerances would be expected to vary quite widely. The coefficient of thermal expansion of copper being different than that of the brass or ceramic, and differential thermal expansion tending to loosen their engagement at their conical surfaces is overcome by the resilient action of spring or gas pressure urging the core into contact with the sleeve thereby maintaining the channel-sealing pressure contact. This not only provides the flame uniformity mentioned but also an improved heat exchange relationship that keeps the core cooler with the resulting actual differential of expansion of the metals minimized. Although sensible heat in the tip is desirable to increase the rate of flame propagation, and thereby permit increased velocity and avoid flashbacks or preignition.

A further object of the invention is to provide a two-piece cutting tip in which the core is free to turn with the sleeve if the sleeve is turned in tightening.

A further object of the invention is to provide a cutting torch head assembly in which a removable cutting tip base or retainer may be left in the torch head with a wrench-tightened assembly as an adapter member and the torch tip core and sleeve assembly received therein under finger pressure tightness with improved performance results and easily releasable low cost tip ends.

The invention also is characterized by a constant predetermined heat exchange pressure contact between the sleeve and core of the tip of any given size over a predetermined short length at the tip to transfer the high heat of the tip end of the core into the copper sleeve for rapid conduction and dissipation externally away from the base of the tip.

In the present invention the flame-forming channels are uniformly limited to a predetermined length at the tip end to provide clearance over the major portion of the core length where the preheat mixture of flowinggases bathes and cools the core at the same time that heat from combustion is absorbed from the core by the copper sleeve whereby the heat is rapidly conducted rearwardly and away from the core by the copper sleeve and is radiated essentially to the air without any major heat exchange conduction back to the core.

The invention also contemplates a controlled coolness at the bases of the core and sleeve which enables the use of a material such as a heat resistant halogenated hydrocarbon elastomer or polymerized fluorinated hydrocarbon.

These being among the objects of the invention, other and further objects will be understood from the claims and the following description of the drawings in which:

FIG. 1 is a schematic view of a flame cutting torch embodying the invention connected in service with to compressed gas cylinders of fuel and oxygen;

FIG. 2 is an enlarged sectional view taken longitudinally through the tip and torch head assembly shown in FIG. 1;

FIGS. 3, 4 and are cross-sectional views taken on lines 3- 3, 4-4 and 5-5 in FIG. 2;

FIG. 6 is an exploded assembly sequence view of the tip elements shown in FIG. 2;

FIG. 7 is a view similar to FIG. 2 illustrating another embodiment of the invention utilizing spring and gas pressure with the parts located prior to a final finger tightening of the tip in operative position;

FIG. 8 is a modification of the embodiment shown in FIG. 7 without a spring in it and after final tightening;

FIG. 9 is a front end view partly in section through the tip securement portion of another embodiment illustrating a bayonet joint securement;

FIG. 10 is a section taken on line 10-10 of FIG. 9;

FIG. 11 is a side elevational view of the embodiment shown in FIGS. 9 and 10;

FIG. 12 is an end view partly in section taken on line 12-12 in FIG. 13;

FIG. 13 is a section taken on line 13-13 in FIG. 12;

FIG. 14 is a longitudinal sectional view similar to FIG. 2 illustrating another embodiment of the invention utilizing the core of FIG. 8 with gas pressure for sealing and a spring for feeling of tightness;

FIG. 15 is a view like FIG. 10 showing a modification of the embodiments illustrated for retaining in assembled relation the tip parts when separate from the torch; and

FIG. 16 is a section taken on line 16-16 of FIG. 15.

THE PREFERRED EMBODIMENTS Referring now to the drawings in further detail, there are two gas supply systems in handling the gases for flame cutting torches, in one (not illustrated) three tanks are employed, one for fuel gas, one for preheat oxygen, and the third for the cutting oxygen. This has been desirable where torch structure and seals may not otherwise maintain a neutral flame. The other system which is illustrated (FIG. 1), employs only two tanks 10 and 15 wherein oxygen for cutting and the preheat mixing is supplied from a single tank 10 through a shutoff valve 11, a two-stage pressure regulator 12, such as described generally in Buttner U.S. Pat. No. 2,362,352, and a hose 13 leading to the torch 14. The fuel gas tank 15 of propane is similarly connected through a shutoff valve 16, regulator 17 and hose 18 to the torch 14. Natural gas can be substituted for tank 15 if natural gas under sufficient pressure is available.

Mixing of preheat gases may be provided in the torch handle 21 or in head 22. In the embodiment illustrated the oxygen is conducted to the lever controlled valve 19 and one of the needle valves 18,, while the fuel gas is conducted to the other needle valve 18,,. Three conduits 23 connect the outlets of the three valves to the torch head 22 (FIGS. 1 and 2).

Although the invention may be used with both systems, the two-tank system is preferred because the invention embodied in the tip 20 on the torch 14 illustrated provides excellent uniformity of flame adjustment. A neutral flame can be set quickly by needle valves 18 while the oxygen is turned ON" by the lever handle and valve 19 at a pressure controlled by the regulator 12. Then when the cutting stream is shut off during preheating of a workpiece at the start of a cut, the flame automatically becomes slightly oxidizing" which for purposes of preheating is a hotter flame since it induces some burning of the workpiece metal which adds to the effect of the flame heat before the cutting stream is turned on. This enables the desirable use of two tanks and also saves the handling of three tanks.

As shown, the head 22 has a generally tapered enlarged cavity 24 formed in it having concentric frustoconical sealing surfaces 29. The passage 25, which is connected to the outlet of the cutting valve 19 enters the cavity 24 at its apex within a frustoconical sealing surface 29a. Beyond the surface 29a the cavity 24 has an annular groove 26 which is in communication with the passage 27 within the surface 2% that delivers low pressure oxygen thereto from the oxygen needle valve 18,, An annular groove 28 is formed in the cavity 24 proximate to its greatest diameter within surface 290 and receives fuel gas through the passage 30 from the needle valve 18,. The head 22 may have an exteriorly threaded extension 31 within which the cavity 24 is formed and this extension receives in threaded engagement a retainer nut 32 having an integral flange 33 that defines a wide internal cylindrical surface 34 having an outwardly flaring mouth 35. The nut 32 secures in place a tip base member 36 which mates with the sealing surfaces and grooves in the cavity.

A longitudinal central conduit 37 is formed in the base 36 and this passage is enlarged adjacent to its downstream end to form a shoulder element 38 with an internal retainer rib 40 spaced a slight distance therefrom to hold the bottom turn of a compression spring 41 in place in those embodiments where it is used. The base 36 is grooved or cut away as at 45 in communication with the groove 26 of the cavity 24 and is also cut away as at 46 to mate with the groove 28 of the cavity 24. Thus, when the base is in place, one annular passage is formed about its exterior by the grooves 26 and 45, and a second an nular passage is formed by the grooves 28 and 46, these passages being in communication, respectively, with the conduit passages 27 and 30.

Running through the base 36 are one or more longitudinally extending passages 47 which communicate with the groove 45 and extend to the outer end of the base preferably through a flat radial end wall 48. For each passage 47 there is formed a passage 50 which extends from the space 46 at an incline and enters the passage 47. Thus, the gases flowing from the grooves. 26 and 28 are confluent and mix in the passages 47. The outer or downstream end of the base may be provided with a radial flange 51 engaged by the retainer nut 32 to serve as a fixed member and hold in place under wrenchtight pressure the conical engagements 29 in sea] relationship by means of the threaded relation 52 between the nut 32 and head 22.

Associated with the base 36 in supported relation is a tip core 44 formed of material such as brass or ceramic, but not limited thereto, and having a body portion 53 which is provided with a central bore or passage 54, the inner or upstream end of which may be enlarged as at 55 is desired. The external wall of the core is cylindrical over a major rear portion 56 and is tapered or inclined as at 57 over the front portion. A plurality of peripherally spaced longitudinal slots or grooves 58 are formed in the exterior of the core around the cutting port 60 and blends rearwardly into the cylindrical portion 56. As shown, particularly in FIG. 6, these slots or grooves 58 are preferably directed radially with respect to the center of the core and their depth in their deepest portion is preferably relatively greater than their width. They preferably are rectangular in cross section as shown in FIG. 5 and of generally constant width throughout their length. It will be understood, however, that these slots may be varied in shape and cross section. It is important, however, that the slots be of sufficient depth in relation to their width to provide a substantial flow area at the ports 61 and a substantial entrance area and space at the inner end of each slot to minimize turbulence of flow at their ports.

At its inner end, the core 44 is provided with a circumferential groove 62 in all embodiments within the confines of the enlarged cylindrical portion 42 of the passage 37 in the base 36. This groove carries 48a O-ring 63 comprised of any material characterized by its ability to withstand elevated temperatures encountered 380 this point, and having a degree of chemical inertness, toughness and rapid recovery from deformation under severe service conditions. For this purpose halogenated hydrocarbon elastomers are highly suitable, including fluorine containing hydrocarbon polymers, fluoroelastomers and fluorinated ethylene-propylene polymers which withstand temperatures of 600 F. and higher. The proprietary fluoroelastomer product known and sold under the name Viton by E. I. du Pont de Nemours & Co., Inc., is suitable for fabrication of the O-ring 63. These polymers may contain both fluorine and chlorine in the molecule as illustrated by chlorotrifluoroethylene polymers. The O-ring is mildly deformed by the flared, opening 39 as the rear end of the core is inserted into place. Thereafter, the O- ring slides in sealed relationship along and within the cylindrical surface 42 and is disposed in cooling relationship between thin-walled metal sections cooled by isothermal expansion of flowing gases, namely, the oxygen stream and preheat mixtures.

Associated with the base and surrounding the core is a sleeve, preferably of copper, comprising a generally tubular body 64 which preferably is externally shouldered at its upstream end as at 65 and tapered at its tip. Internally the central bore 66 has a flared mouth as at 67 at its inner end and is forwardly tapered as at 68 preferably throughout its major length towards its outer end to fit over the taper 57 of the core.

Referring to the taper fit between the core at 57 and the sleeve at 68, the included angles are approximately 8 with a plus tolerance and a negative tolerance of a little less than W for the sleeve and core, respectively. The physical contact area 70 therefore occurs at the tip end of the core and under longitudinal pressure extends effectively approximately a quarter of an inch rearwardly therefrom. The sleeve terminally overhangs the core and approximately a minimum of 4 one thirty-second of an inch and a maximum of one-eighth depending upon the tip size. The sleeve taper extends inwardly from the contact area 70 over the major length of the core to provide a substantially circular chamber 91 around the core through which the preheat gas mixture flows rapidly from the passages 47 in direct cooling contact with the core. This passage narrows down in cross-sectional area to accelerate the preheat gas flow which is gradually divided into the grooves 58 that terminally become passages as confined by the sleeve. The preheat streams of gas mixtures have turbulence removed from them, as already mentioned, as they flow in the grooves 58 and finally are discharged through the ports 61 where they are ignited and provide a cluster of uniform flames around the cutting port.

The flange 69 on the sleeve is elongated rearwardly from the shoulder 65 and is provided with an external annular groove 72 which receives an O-ring 73 also of polymerized fluorohydrocarbon, and preferably a copolymer of vinylidene fluoride and hexafluoropropylene. The O-ring 73 engages in sealed relationship the cylindrical surface 34 on the retainer nut 32 when the inner squared end 74 thereof abuts against the end wall 48 of the base member 36. A cup-shaped tip retainer nut 75 serves as a releasable member and threadedly engages the retainer nut 32 with finger-manipulated threads at 76 and has an internal flange 77 whichengages the shoulder 65 of the sleeve and compresses spring 41 to hold the sleeve and core in place by the pressure of the spring 41 when present and the pressure of the cutting oxygen when the spring is omitted. The spring pressure maintains the contacting relationship at 70 and provides a tactual perception of tightening to assist the manual tightening of the tip retainer nut without tools. Preferably, as shown in FIG. 6, the external surface 78 is not adapted for wrenching and is shaped to remind the user that it is to be finger-tightened.

The parts are assembled in the order shown in FIG. 6 in which the base member is inserted into the tapered cavity 24 in the head 22 and held there as a semipermanent part under wrench tightness by the retainer nut 32. The spring 41, when used, is snapped into place as held by the rib 40 and the tip assembly with any one of a number of interchangeable cores of different port sizes can be mounted by inserting the rear end with an O-ring on it into the base member to rest against the spring 41 and then finger-tightening the nut 75 as mentioned.

It will be appreciated that the sleeve, core and retainers can be assembled first and then wrench-tightened to the head with the base in place for operation without damage to the parts if for any reason this method of assembly is inadvertently or intentionally used. The spring still protects and seals the parts when present, and when not present there is enough space to prevent damage.

In the modifications shown in the other FIGS. many of the elements are identical, or substantially so, to those described above and like elements have been given identical numerals with or without suffix letters if any structural differences are significant.

Referring now to the remaining FIGS., other than FIG. 13, the head 22 and base 36 structures differ in that the fuel and oxygen for the preheat ports are premixed prior to the torch head, thereby requiring only a dual flow system, namely, the cutting oxygen passages including conduits 25, 37 and cylindrical portion 42 and the preheat mixture passage including the groove 26a and passages 470 leading to the core and sleeves. Like in FIG. 2 the sleeve 64 can be slipped over the core 44 and the tip retainer nut 75 applied and finger turned until compression of the spring 41 begins as represented in FIG. 7. Thereafter, finger tightening compresses the spring and provides the feel of tightening a threaded relationship which indicates a full tightness has been accomplished when the sleeve goes solid against the base member. The spring 41 likewise establishes a predetermined pressure contact between the sleeve and core at their tip ends, as represented in FIG. 2.

In the event the core is of a ceramic material the tightening of the tip retainer nut will not damage the core even if a wrench is used since the resilient support of the core by spring or pressure establishes and limits the contact pressure to which the ceramic is subjected. Moreover, because of its negligible heat absorption and conductivity, a ceramic core is preferred for many applications not only for a cost saving but also because of their excellent performance.

In FIGS. 9, 10 and 11 a fast-acting coupling is employed in place of the threaded engagement 76 of FIGS. 2, 7 and 8. The spring 41 enables the use of the fast action of a bayonet jointtype securement and maintains the securement for the tip retainer wherein radially disposed screws or pins 80 are secured in the stock of the flange 33a on the retainer nut 32 and a cup-shaped cap 81 has bayonet-type recesses 82 in the marginal edge 83 of its cylindrical wall 84 portion which coact therewith merely by aligning the pins and recesses, pressing inwardly on the cap and twisting it clockwise. Release of the tip is accomplished by reversal of the above steps and directions.

In FIGS. 12 and 13, in order to reduce the overall radial dimension of FIGS. 10 and 1 1, the pins 80b are mounted in the flange 33b whereby their axes are parallel with the tip axis and the flange 77b is provided with key hole slots 82b to receive the heads 85b through the key hole enlargement portion for movement into the narrow portion with the same motions described in connection with FIGS. 9, 10 and 11.

In FIG. 14 where it is desired to compact the overall length of the head and tip and reduce space between the core and base as far as the cutting oxygen supply is concerned, the inner end 48a of the core is arranged to come close if not bottom against the shoulder element 38a by the action of the compression spring 41b. This spring as located between the flange 77 on the tip retaining nut 75 and the shoulder 65 on the sleeve 64a permits the core freedom to move outwardly to tighten its sealing relationship with the sleeve if and when the pressure of cutting oxygen upon its inner end 38a is greater than the strength of the compressed spring 41b. Thus in a direct relationship the sealing relationship between the sleeve and core at the grooves can be related to the pressure of the cutting oxygen yet the core is resiliently held against looseness when that pressure is lacking as when the cutting stream is turned off. In this embodiment, not only is the flange 69b narrow, but the space and metal stock shown to be broken away in FIG. 14 can be saved in the head and base members.

Accordingly, the embodiments of FIGS. 6 and 14 can be considered as representing preferred embodiments because the spring 41 can be eliminated from FIG. 2 with a saving in material and the pressure of the cutting oxygen provides the resilient sealing pressure; the pressure of the cutting oxygen in FIGS. 2, 7 and 13 is additive to the spring 41 pressure and a light spring can be employed merely to prevent looseness; while in FIG. 14, as just noted the pressure of the oxygen is that which determines the sealing pressure and the core is spring supported against looseness at all times.

Referring now to FIGS. 15 and 16, a modification for all the other embodiments is shown wherein a circumferential groove 85 receives a flat band C-spring 86 which finger portions 87 have been cut from the edge and flexed outwardly to engage the inner wall of sleeve 64 at 88 in frictional relationship to resist separation of the sleeve 64 and core 44 when being removed together from the torch. This greatly reduces the danger of the core dropping out of the sleeve and being damaged by dropping, in the handling of the tip assembly. Moreover, since only the fingers are exposed to the gas flow, there will be very little turbulence induced in the preheat mixture and such will not survive during the flow in the distance remaining to the preheat ports.

Having thus described the invention it will be apparent how the objects are accomplished and how various and further modification can be made without departing from the spirit of the invention.

What is claimed is:

1. In a device of the class described, the combination of:

an elongated core means having a cylindrical external wall portion at its inner end and a frustoconical tapering external surface at its forward end with longitudinal channels recessed therein tapering into said cylindrical wall portion,

a base member having a central enlarged compartment at its forward end to define a forward-facing internal shoulder element therein and a cylindrical wall receiving said external cylindrical wall portion,

one of said cylindrical wall portions having a radially opening annular groove adjacent to its inner end,

sealing means carried concentrically in said annular groove to telescope in sliding relationship against the other cylindrical wall portion to hold them in concentricity,

a sleeve member having a tapering internal surface corresponding with said external tapering surface at the forward end to engage therewith and a shoulder element at the inner end thereof,

a retainer means for supporting said sleeve member and said base member in assembled relationship, and

resilient means disposed between one of said members and one of said core and retaining means urging said surfaces into heat transfer contact with each other under pressure at their forward ends to convert said channels into conduits and discrete ports.

2. The combination called for in claim 1 in which said base member has a central conduit conducting a cutting gas to said compartment,

said core means having a central conduit conducting said cutting gas from said compartment to an outlet port on the forward end of said core centrally located with said channel conduits,

said means carried in said annular groove sealing the space between said base member and core means at said telescoping relationship whereby the pressure of cutting gas in said compartment comprises said resilient means and is effective over the inner end area of the core means.

3. The combination called for in claim 1 in which said base member has preheat gas conduits communicating with said channel conduits,

said retainer means having an internal cylindrical wall section, said shoulder element having a cylindrical wall section, one of said cylindrical wall section having a radially opening annular groove, and

resilient means carried in the last-mentioned annular groove to seal in sliding relationship against the other cylindrical wall section to seal said last sliding relationship against escape therethrough of preheat fuel gas mixtures to atmosphere.

4. The combination called for in claim 1 in which said resilient means comprises a spring means disposed in said compartment between said shoulder member and core means, and

said retainer means includes a releasable member and a fixed member releasably interengaging each other to compress said spring means.

5. The combination called for in claim I in which: said retainer means includes a releasable member having an internal flange thereon, and

said resilient means is disposed between said shoulder element on said sleeve and said internal flange.

6. The combination called for in claim 1 in which said core means has a second annular groove thereon and including,

spring means 86 carried in the second annular groove engaging said sleeve member in assembly retaining relationship.

7. The combination called for in claim 1 in which said retainer means includes a retainer nut for holding said base member,

a cup-shaped releasable member rotatively engaging said shoulder element on the sleeve member, and

finger-manipulating means releasably for compressing said resilient means and securing said retainer nut and cup member in assembled relation under the force of said compression.

8. The combination called for in claim 7 in which said finger-manipulated means comprises mating threads carried by the wall of the cup member and said retainer nut.

9. The combination called for in claim 7 in which said finger-manipulated means comprises a bayonet-type joint.

10. The combination called for in claim 1 in which the means carried in said annular groove comprises a material characterized by its ability to withstand elevated temperatures, chemical inertness, toughness and elasticity.

l 1. In a device of the class described the combination of:

an elongated core member having a cylindrical external wall portion terminating at its inner end in an end wall and a external surface tapering at approximately 8 at its outer end with longitudinal fuel mixture gas channels recessed therein,

a base member having a central gas-conducting conduit enlarged at its forward end to define internally a forwardfacing shoulder therein and a cylindrical wall telescopically receiving said external cylindrical wall portion a variable distance between the end wall and shoulder,

one of said cylindrical wall portions having a radially opening annular groove,

means carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion,

means having a resilient body disposed between the inner end wall of said core member and said shoulder to urge said coremember in .1 relative forward direction from said shoulder.

12. In a device of the class described the combination of:

an elongated core member having a conduit centrally therethrough and having a cylindrical external wall portion with a wall at its inner end and a tapering external surface at its outer end over a minor portion of its length with longitudinal fuel mixture gas channels recessed therein and extending into the cylindrical wall portion,

a sleeve member having a tapering internal surface corresponding with said external tapering surface extending a distance greater than said minor portion to provide gradually converging circular walls defining a tapering distribution space leading to said gas channels,

a base member having conduits in communication with said tapering space and a central gas-conducting conduit enlarged at its forward end to define internally a forward facing shoulder therein and a cylindrical wall telescopically receiving said external cylindrical wall portion a variable distance between the wall and shoulder and in communication with said conduit in said core member,

one of said cylindrical wall portions having a radially opening annular groove,

means carried by said annular groove to seal in sliding relationship against the other cylindrical all portion,

spring means disposed between said core member wall and said shoulder urging said core means in a relative forward direction from said shoulder, and

means releasably interengaging said base member and said sleeve member to compress said spring means and hold said sleeve member into pressure contact with said core member.

13. In a device of the class described the combination of:

an elongated core member having a cylindrical external wall portion with a wall at its inner end and a tapering external surface at its forward end with circumferentially spaced longitudinal channels recessed therein,

means for supporting said core member having a central enlarged compartment at its forward end to define an internal cylindrical wall receiving said external cylindrical wall portion and a forward-facing shoulder therein,

one of said cylindrical wall portions having a radially opening annular groove,

resilient means carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion,

spring means disposed between said core member wall and shoulder urging said core member in a relative forward direction from said shoulder, and

sleeve means carried by said supporting means and having a circular surface internally engaging said core member at the tip thereof to oppose said forward action of the spring under radially directed pressure contact and convert said channels into conduits having discrete ports outwardly bordered by said circular surface.

14. In a flame cutting torch of the class described a head member with a plurality of gas passages opening in radially spaced relationship disposed between frustoconical surfaces and a conduit centrally therethrough, the combination of a base member having radially opened mating frustoconical surfaces defining a central gas-conducting conduit through the center one thereof enlarged at its forward end to internally define a forward-facing shoulder element therein and a cylindrical wall defining a compartment receiving oxygen centrally from one of said gas passages,

retainer nut means secured to said head member to clamp said frustoconical surfaces in sealing relationship against each other and having a cylindrical surface beyond said base member,

an elongated core means having a conduit centrally therethrough and a cylindrical external wall portion with a wall at its inner end received in said compartment and a tapering external surface of approximately 8 at its forward end with longitudinal channels recessed therein,

one of said cylindrical wall portions having a radially extending annular groove,

resilient means of heat-resistant material carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion under constant sealing pressure, a sleeve member having a tapering internal surface corresponding with and extending a greater distance than said external tapering surfaces at the forward end and a shoulder member at the inner end thereof defining a cylindrical surface received in the other cylindrical surface,

one of said cylindrical surfaces having a radially extending annular groove,

resilient means of heat resistant material carried by the lastmentioned annular groove to engage and seal the space between said cylindrical surfaces,

retainer means interconnecting said sleeve member shoulder element and said retainer nut to draw said sleeve member and core member towards the head, and

compression spring means in said compartment between said shoulder element and said core wall compressed by said core movement to bring said tapering surfaces into heat transfer contact with each other under pressure to convert said channels into preheat conduits with discrete ports and provide a tapering annular passage opening into said preheat conduits, and

said base member having conduits interconnecting other of said gas passages to said annular passage.

15. In a device of the class described the combination of:

an elongated core means having a cylindrical external wall portion with a wall at its inner end and a tapering external surface at its forward end with longitudinal channels recessed therein,

a base member having a central gas-conducting conduit enlarged at its forward end to define internally a forwardfacing wall element therein and a cylindrical wall receiving said external cylindrical wall portion,

one of said cylindrical wall portions having a radially opening annular groove,

means carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion,

a sleeve member having a tapering internal surface corresponding with said external tapering surfaces at the forward end and a shoulder element at the inner end thereof,

a retainer means for interengaging said sleeve member and said base member to support them in rigid relationship,

and compressed resilient means disposed between one of said means and one of said elements bringing said surfaces into heat transfer contact with each other under pressure to convert said channels into conduits converging at approximately 8C to the axis of said tapering internal surfaces and terminating with discrete ports.

16. The combination called for in claim 15 in which said resilient means includes a compression spring urging said sleeve and core into telescoping relationship.

17. The combination called for in claim 15 in which said core means has a gas conduit axially through it of a reduced size at its forward end and in communication with said central enlarged compartment,

a central conduit in said base member of a size greater than said reduced size for supplying gas under pressure to said central enlarged compartment,

said resilient means including a body of said gas supplied to said central enlarged compartment under pressure to urge said core means into said sleeve member.

18. The combination called for in claim 17 in which said resilient means includes a spring interengaging one of said means and one of said members to urge said sleeve member over the core means.

19. The combination called for in claim 15 in which said resilient means includes a compression spring and a body of gas under pressure in said compartment. 

1. In a device of the class described, the combination of: an elongated core means having a cylindrical external wall portion at its inner end and a frustoconical tapering external surface at its forward end with longitudinal channels recessed therein tapering into said cylindrical wall portion, a base member having a central enlarged compartment at its forward end to define a forward-facing internal shoulder element therein and a cylindrical wall receiving said external cylindrical wall portion, one of said cylindrical wall portions having a radially opening annular groove adjacent to its inner end, sealing means carried concentrically in said annular groove to telescope in sliding relationship against the other cylindrical wall portion to hold them in concentricity, a sleeve member having a tapering internal surface corresponding with said external tapering surface at the forward end to engage therewith and a shoulder element at the inner end thereof, a retainer means for supporting said sleeve member and said base member in assembled relationship, and resilient means disposed between one of said members and one of said core and retaining means urging said surfaces into heat transfer contact with each other under pressure at their forward ends to convert said channels into conduits and discrete ports.
 2. The combination called for in claim 1 in which said base member has a central conduit conducting a cutting gas to said compartment, said core means having a central conduit conducting said cutting gas from said compartment to an outlet port on the forward end of said core centrally located with said channel conduits, said means carried in said annular groove sealing the space between said base member and core means at said telescoping relationship whereby the pressure of cutting gas in said compartment comprises said resilient means and is effective over the inner end area of the core means.
 3. The combination called for in claim 1 in which said base member has preheat gas conduits communicating with said channel conduits, said retainer means having an internal cylindrical wall section, said shoulder element having a cylindrical wall section, one of said cylindrical wall section having a radially opening annular groove, and resilient means carried in the last-mentioned annular groove to seal in sliding relationship against the other cylindrical wall section to seal said last sliding relationship against escape therethrough of preheat fuel gas mixtures to atmosphere.
 4. The combination called for in claim 1 in which said resilient means comprises a spring means disposed in said compartment between said shoulder member and core means, and said retainer means includes a releasable member and a fixed member releasably interengaging each other to compress said spring means.
 5. The combination called for in claim 1 in which: said retainer means includes a releasable member having an internal flange thereon, and said resilient means is disposed between said shoulder element on said sleeve and said internal flange.
 6. The combination called for in claim 1 in which said core means has a second annular groove thereon and including, spring means 86 carried in the second annular groove engaging said sleeve member in assembly retaining relationship.
 7. The combination called for in claim 1 in which said retainer means includes a retainer nut for holding said base member, a cup-shaped releasable member rotatively engaging said shoulder element on tHe sleeve member, and finger-manipulating means releasably for compressing said resilient means and securing said retainer nut and cup member in assembled relation under the force of said compression.
 8. The combination called for in claim 7 in which said finger-manipulated means comprises mating threads carried by the wall of the cup member and said retainer nut.
 9. The combination called for in claim 7 in which said finger-manipulated means comprises a bayonet-type joint.
 10. The combination called for in claim 1 in which the means carried in said annular groove comprises a material characterized by its ability to withstand elevated temperatures, chemical inertness, toughness and elasticity.
 11. In a device of the class described the combination of: an elongated core member having a cylindrical external wall portion terminating at its inner end in an end wall and a external surface tapering at approximately 8* at its outer end with longitudinal fuel mixture gas channels recessed therein, a base member having a central gas-conducting conduit enlarged at its forward end to define internally a forward-facing shoulder therein and a cylindrical wall telescopically receiving said external cylindrical wall portion a variable distance between the end wall and shoulder, one of said cylindrical wall portions having a radially opening annular groove, means carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion, means having a resilient body disposed between the inner end wall of said core member and said shoulder to urge said core member in a relative forward direction from said shoulder.
 12. In a device of the class described the combination of: an elongated core member having a conduit centrally therethrough and having a cylindrical external wall portion with a wall at its inner end and a tapering external surface at its outer end over a minor portion of its length with longitudinal fuel mixture gas channels recessed therein and extending into the cylindrical wall portion, a sleeve member having a tapering internal surface corresponding with said external tapering surface extending a distance greater than said minor portion to provide gradually converging circular walls defining a tapering distribution space leading to said gas channels, a base member having conduits in communication with said tapering space and a central gas-conducting conduit enlarged at its forward end to define internally a forward facing shoulder therein and a cylindrical wall telescopically receiving said external cylindrical wall portion a variable distance between the wall and shoulder and in communication with said conduit in said core member, one of said cylindrical wall portions having a radially opening annular groove, means carried by said annular groove to seal in sliding relationship against the other cylindrical all portion, spring means disposed between said core member wall and said shoulder urging said core means in a relative forward direction from said shoulder, and means releasably interengaging said base member and said sleeve member to compress said spring means and hold said sleeve member into pressure contact with said core member.
 13. In a device of the class described the combination of: an elongated core member having a cylindrical external wall portion with a wall at its inner end and a tapering external surface at its forward end with circumferentially spaced longitudinal channels recessed therein, means for supporting said core member having a central enlarged compartment at its forward end to define an internal cylindrical wall receiving said external cylindrical wall portion and a forward-facing shoulder therein, one of said cylindrical wall portions having a radially opening annular groove, resilient means carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion, spring means disposed between said core member wall and shoulder urging said core member in a relative forward direction from said shoulder, and sleeve means carried by said supporting means and having a circular surface internally engaging said core member at the tip thereof to oppose said forward action of the spring under radially directed pressure contact and convert said channels into conduits having discrete ports outwardly bordered by said circular surface.
 14. In a flame cutting torch of the class described a head member with a plurality of gas passages opening in radially spaced relationship disposed between frustoconical surfaces and a conduit centrally therethrough, the combination of a base member having radially opened mating frustoconical surfaces defining a central gas-conducting conduit through the center one thereof enlarged at its forward end to internally define a forward-facing shoulder element therein and a cylindrical wall defining a compartment receiving oxygen centrally from one of said gas passages, retainer nut means secured to said head member to clamp said frustoconical surfaces in sealing relationship against each other and having a cylindrical surface beyond said base member, an elongated core means having a conduit centrally therethrough and a cylindrical external wall portion with a wall at its inner end received in said compartment and a tapering external surface of approximately 8* at its forward end with longitudinal channels recessed therein, one of said cylindrical wall portions having a radially extending annular groove, resilient means of heat-resistant material carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion under constant sealing pressure, a sleeve member having a tapering internal surface corresponding with and extending a greater distance than said external tapering surfaces at the forward end and a shoulder member at the inner end thereof defining a cylindrical surface received in the other cylindrical surface, one of said cylindrical surfaces having a radially extending annular groove, resilient means of heat resistant material carried by the last-mentioned annular groove to engage and seal the space between said cylindrical surfaces, retainer means interconnecting said sleeve member shoulder element and said retainer nut to draw said sleeve member and core member towards the head, and compression spring means in said compartment between said shoulder element and said core wall compressed by said core movement to bring said tapering surfaces into heat transfer contact with each other under pressure to convert said channels into preheat conduits with discrete ports and provide a tapering annular passage opening into said preheat conduits, and said base member having conduits interconnecting other of said gas passages to said annular passage.
 15. In a device of the class described the combination of: an elongated core means having a cylindrical external wall portion with a wall at its inner end and a tapering external surface at its forward end with longitudinal channels recessed therein, a base member having a central gas-conducting conduit enlarged at its forward end to define internally a forward-facing wall element therein and a cylindrical wall receiving said external cylindrical wall portion, one of said cylindrical wall portions having a radially opening annular groove, means carried by said annular groove to seal in sliding relationship against the other cylindrical wall portion, a sleeve member having a tapering internal surface corresponding with said external tapering surfaces at the forward end and a shoulder element at the inner end thereof, a retainer means for interengaging said sleeve member and said base member to support them in rigid relationship, and compressed resilient means disposed between one of said means and one of said elements bringing saiD surfaces into heat transfer contact with each other under pressure to convert said channels into conduits converging at approximately 8*0 to the axis of said tapering internal surfaces and terminating with discrete ports.
 16. The combination called for in claim 15 in which said resilient means includes a compression spring urging said sleeve and core into telescoping relationship.
 17. The combination called for in claim 15 in which said core means has a gas conduit axially through it of a reduced size at its forward end and in communication with said central enlarged compartment, a central conduit in said base member of a size greater than said reduced size for supplying gas under pressure to said central enlarged compartment, said resilient means including a body of said gas supplied to said central enlarged compartment under pressure to urge said core means into said sleeve member.
 18. The combination called for in claim 17 in which said resilient means includes a spring interengaging one of said means and one of said members to urge said sleeve member over the core means.
 19. The combination called for in claim 15 in which said resilient means includes a compression spring and a body of gas under pressure in said compartment. 